This is a request for continuation of the joint training program in psychiatric epidemiology and biostatistics at the Harvard School of Public Health. The principal objectives of the training program are to educate promising pre- and postdoctoral students to become epidemiological and biostatistical scientists in psychiatric research. A total of ten predoctoral and six postdoctoral trainees are requested. The last few decades have seen substantial progress in many areas of psychiatric epidemiology and biostatistics, including knowledge about prevalence and incidence rates for basic disorders, improvements in diagnostic classification systems and measurement instruments, research in the genetic origins of mental illness, drug therapy for chronic mental illness and brain imaging. Rapid developments in the basic sciences of epidemiology and biostatistics provide opportunities for pushing further the frontiers of research in psychiatric disorders, in understanding the natural history, genetic and environmental risk factors, and developing better treatment strategies. In order to take advantage of this opportunity, there exists a critical need for high level technical training in the companion core disciplines of epidemiology and biostatistics. The Departments of Epidemiology and Biostatistics at HSPH are noted world wide as leading centers for training in biostatistics and epidemiology. Our joint training program, initiated in 1991, has rapidly expanded and flourished under the leadership of Drs. Ming Tsuang and Nan Laird, Director and Co-Director of the program. Both departments have a strong record of producing high quality doctoral trainees, and our joint program has emerged as an important component of the training activities of each department. Doctoral trainees typically take two full years of coursework, with a concentration either in biostatistics or epidemiology, and often a minor concentration in the other field. In addition, each trainee must take a minor concentration in psychiatric epidemiology, or an allied substantive field related to mental health. Doctoral students must pass a written and oral qualifying exam, usually by the third year of doctoral studies. Upon completion of the oral exam, a research committee is formed of three faculty, generally with at least one faculty member from biostatistics and one from epidemiology. The postdoctoral training program in epidemiology offers degree training to psychiatrists wishing to specialize in epidemiologic research; nondegree postdoctoral training is offered for Ph.D. 's or Sc.D. 's with a solid training in epidemiology, biostatistics or a related field who wish to specialize in mental health. An important part of the training for both predoctoral and postdoctoral fellows is attendance at regular seminars and colloquiums in psychiatric biostatistics and epidemiology, and participation in placements providing hands on experience in collaborative research in ongoing psychiatric research in the greater Boston area.